Winning by a nose: Dog behavior is linked to head shape

Short-nosed dog breeds, like French Bulldogs and Pugs, remain immensely popular. But are they truly better companion animals than other breeds? According to a new study by ethologists at Eötvös Loránd University (ELTE), short noses may indeed influence behavior — but just as important are small body size and owner treatment. These dogs are often spoiled and less frequently trained, which affects their behavior. While short-nosed dogs may be calmer and less reactive, these potential benefits often fail to emerge without proper upbringing.

Short-nosed breeds top popularity charts in many countries, despite suffering from breathing difficulties, allergies, and skin or eye issues. Researchers have long sought to understand what makes these dogs so appealing — what outweighs the burden of chronic health problems? Besides their baby-like faces, their behavior may also play a decisive role. Owners often describe them as interactive, friendly, and playful.

Earlier studies also found that they make eye contact with humans more frequently than other breeds and are more effective at following human gestures.

But do behavioral traits associated with flat faces truly stem from head shape, or are they the result of different keeping practices? To find out, ELTE researchers compared four personality traits and four behavioral problems in over 5,000 purebred dogs. They examined these in relation to head shape, body size, keeping conditions, and owner characteristics, using questionnaire data collected in Germany.

When only head shape is considered, short-nosed dogs appear calmer and bolder than long-nosed dogs. But they also show less favorable traits: they are harder to train, reluctant to return when called, and overreact to guests arriving at the house. Further analysis revealed that the typical short-nosed dog is more often small-sized, young, unneutered, untrained, kept exclusively indoors, and allowed on the bed more frequently than other dogs. Their owners are typically young women who have never had a dog before, live alone, and spend a lot of time with their dog, who they primarily chose for companionship. These factors themselves also influence behavior and may obscure the direct effects of head shape. For example, experienced owners usually have better-trained dogs; older dogs are calmer; and smaller dogs are more likely to jump up on people.

In the next phase, the researchers used more detailed statistical analyses to examine whether various factors suppressed or amplified the link between head shape and behavior.

“We found that the low trainability of short-nosed dogs is mainly due to their small body size and lack of training — not their head shape.

When we control for these influences, there’s no difference in trainability across head shapes,” says Borbála Turcsán, a member of the MTA-ELTE ‘Momentum’ Companion Animal Research Group. However, the analyses also showed that some behavioral traits are directly linked to head shape. For instance, short-nosed dogs are innately less friendly toward other dogs, but this effect is offset by their youth, since younger dogs are generally more sociable. On the plus side, when the effects of lack of training, small size, and pampering are accounted for, it turns out that short-nosed dogs are genetically less likely to jump up on people, pull on the leash, or react excessively when guests arrive.

“Calmness, boldness, and poor recall response are all traits specific to short-headed dogs. These behavioral traits are directly connected to head shape and remain significant even when we control for background factors,” Turcsán adds.

Why might behavior be directly related to head shape? “The brains of short-nosed dogs are more rounded, and their patterns of brain activity differ from those of other breeds, so it’s easy to imagine that their brains regulate behavior differently,” explains Enikő Kubinyi, head of the Department of Ethology at ELTE. “It’s also possible that dogs with breathing difficulties, pain, or musculoskeletal issues move less and seek comfort, which owners interpret as calm behavior.”

Moreover, their popularity may partly stem from their vulnerability and need for support.

The study’s key takeaway is that short-nosed dogs have some innate positive traits — primarily calmness and low reactivity — but these are often masked by the negative effects of small size and lack of training. For example, while short-nosed dogs are generally less likely to pull on the leash, if they are never taught how to behave on a leash, their innate tendencies won’t help.

That’s why the researchers stress that even flat-faced dogs need consistent training — not pampering — for their good traits to shine through.